<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>测试</title>
    <style>
      canvas {
        width: 600px;
        height: 400px;
        border: 1px solid red;
      }
    </style>
  </head>

  <body>
    <div id="root">
      <canvas id="cav" width="600" height="300"></canvas>
    </div>
  </body>
</html>
